DE1237561B - Process for the preparation of 7-chloro-4-thiaoenanthic acid - Google Patents

Description

UNDESREPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Inta .:

C07C

German class: 12 ο - 23/03

Number: 1 237 561

File number: St 25505IV b / 12 ο

Filing date: June 8, 1966

Open date: March 30, 1967

The invention relates to the production of 7-chloro-4-thiaenanthic acid, one not yet in the Literature mentioned connection. This new substance can be used as a starting product for the Manufacture e.g. B. of 7-amino-4-thiaenanthic acid, an important amino acid.

A process has now been found for the preparation of 7-chloro-4-thiaenanthic acid, which thereby is characterized in that ß-mercaptopropionic acid, its nitrile, esters or salts in the presence of a Reacts solvent under irradiation with ultraviolet light with allyl chloride and from the reaction mixture obtained, optionally after hydrolysis, the 7-chloro-4-thiaenanthic acid in the usual way Way wins.

No special precautions regarding temperature and pressure are necessary for the reaction of the starting materials. The reaction can be carried out under atmospheric pressure at room temperature, e.g. B. 10 to 30 ⁰ C, are carried out. so

When carrying out the reaction, irradiation with ultraviolet rays is necessary. A very slow reaction is achieved by exposure to the sun's rays, and at Use of the usual sources of radiation, ultraviolet rays, e.g. B. mercury lamps, which Delivering rays with a wavelength below 3000 angstroms, the response is mostly within 1 to Finished 2 hours.

In the reaction according to the invention there is an addition of / ί-mercaptopropionic acid to allyl chloride instead of. An ester or a salt or the nitrile of ß-mercaptopropionic acid can also be used to be cooked out. In this reaction it is not necessary to use any of the starting materials in excess Apply amount so that the reaction is usually carried out with equimolecular amounts.

It has also been found that the reaction is promoted and the formation of undesirable by-products is reduced when the reaction is in the presence of inert gas, ζ. Β. Hydrogen or Nitrogen. This can be done easily by using an inert gas stream passes through the reaction mixture. The amount of gas can be varied and z. B. 0.1 to 5 moles of hydrogen per mole of allyl chloride.

The reaction is carried out in a solvent. Examples of suitable solvents are: hydrocarbons such as benzene and polar solvents such as alcohols. The amount of solvent can be varied. Usually an amount by weight of solvent is used which corresponds to the amount by weight of processes for the preparation of
7-chloro-4-thiaenanthic acid

Applicant:

Stamicarbon N.V., Heerlen (Netherlands)

Representative:

Dr. F. Zumstein, Dr. E. Assmann

and Dr. R. Koenigsberger, patent attorneys,

Munich 2, Bräuhausstr. 4th

Named as inventor:
Jozef Aloys Thoma, Vaals;
Johannes Wilhelmus Gielkens,
Werner Reichrath, Geleen (Netherlands)

Claimed priority:

Netherlands 9 June 1965 (6 507 299)

of the starting materials almost corresponds, so that the reaction mixture is about 50 percent by weight solvent contains.

Assuming a salt of / I-mercaptopropionic acid, z. B. from an alkali metal salt, the corresponding salt of 7-chloro-4-thiaenanthic acid educated. Such a salt can be converted into 7-chloro-4-thiaenanthic acid by treatment with an equivalent amount of acid realize.

If one starts from the nitrile of ß-mercaptopropionic acid, the product of the addition reaction is 7-chloro-4-thiaenanthic acid nitrile. This hitherto unknown substance can be removed in the usual way, usually by treatment with a Acid, convert to 7-chloro-4-thiaenanthic acid.

The esters of / ϊ-mercaptopropionic acid, which as Starting materials that can be used can be selected from the group of aliphatic and cycloaliphatic and aromatic esters can be selected. Examples of suitable esters are: methyl, ethyl, isopropyl, Butyl, cyclohexyl and phenyl esters of ß-mercaptopropionic acid. When using an ester as a starting material becomes the corresponding ester of 7-chloro-4-thiaenanthic acid as the product of the addition reaction educated. In the usual way, e.g. B. by hydrolysis with the aid of an acid, the ester can be converted to 7-chloro-4-thiaenanthic acid realize. In this hydrolysis

709 547/432

it is recommended that the alcohol formed during the hydrolysis reaction, for. B. by distillation, to remove, thereby promoting hydrolysis.

Used for the addition reaction of / S-mercaptopropionic acid started out and an alcohol is used as a solvent, then ester formation takes place instead of. An ester is then to be expected when working up the reaction product.

The recovery of 7-chloro-4-thiaenanthic acid, which is liquid at room temperature, from the reaction product can be in the usual way, for. B. by distillation perform.

Example I.

In a reaction vessel (quartz) of VaI content equipped with a stirrer, 38.2 g of allyl chloride (0.5 mol) in 80 ml of benzene are mixed with 52 g of β-mercaptopropionic acid. The reaction mixture is irradiated I ¹ I ₂ times with ultraviolet rays at a temperature of 22 ° C while a stream of hydrogen (5 1 per hour, measured at 0 ⁰ C and 1 atm) is passed.

The benzene is then removed by distillation and the residue is distilled in vacuo.

74.7 g of 7-chloro-4-thiaenanthic acid (boiling point 145 ° C. at 1.5 mm Hg) are obtained, which corresponds to a yield of 82 ° / ₀ .

Example II

38.2 g of allyl chloride are placed in a VaI reaction vessel (quartz) equipped with a stirrer (0.5 mol) dissolved in 80 ml of ethanol, after which 67 g of ethyl ester of / 9-mercaptopropionic acid were added will. The reaction mixture is at a temperature of 26 ° C for 2 hours with ultraviolet Rays irradiated.

Then is distilled, wherein the ethanol is recovered first and then 84.5 7-chloro-4-thiaönanthsäureäthylester obtained (boiling point 118 ⁰ C at 1.5 mmHg) (yield 80%).

52.6 g of the ester obtained are introduced into 250 ml of concentrated hydrochloric acid; the mixture is boiled under reflux for about an hour. It is then evaporated to dryness and the The residue is boiled again in 250 ml of hydrochloric acid for about an hour. This hydrochloric acid treatment is done finally repeated again.

41 g of 7-chloro-4-thiaenanthic acid are obtained (yield 90%, based on the ester).

Example III

38.2 g of allyl chloride (0.5 mol) in 100 ml of toluene are mixed with 43.5 g of β-mercaptopropionitrile (0.5 mol) in a reaction vessel (quartz) of VaI content equipped with a stirrer. The reaction mixture is irradiated with ultraviolet rays at a temperature of 25 ^{° C. for 2 hours.}

It is then distilled, and after recovery of the toluene, 69.5 g of 7-chloro-4-thiaenanthic acid nitrile (boiling point 115 ° C. at 1.5 mm Hg) are obtained (yield 85 ° / ₀ ).

41 g of the nitrile obtained are refluxed for 1 hour in 250 ml of concentrated hydrochloric acid »5 cooked, after which it is evaporated to dryness. To separate the ammonium chloride formed is the product extracted with ether; then the ether is evaporated.

41 g of 7-chloro-4-thiaenanthic acid are obtained (yield 90%).

Claims (1)

Claim: Process for the preparation of 7-chloro-4-thiaenanthic acid, characterized in that that one / S-mercaptopropionic acid, its nitrile, esters or salts in the presence of a solvent reacts with allyl chloride under irradiation with ultraviolet light and from the reaction mixture obtained, optionally after hydrolysis, the 7-chloro-4-thiaenanthic acid in the usual way Way wins. 709 547/432 3.67 © Bundesdruckerei Berlin